/*
 * NBests.cpp
 *
 *  Created on: 24 Aug 2016
 *      Author: hieu
 */

#include <boost/foreach.hpp>
#include "NBests.h"
#include "../Manager.h"
#include "../../System.h"

using namespace std;

namespace Moses2
{
namespace SCFG
{
NBests::NBests(const SCFG::Manager &mgr,
		const ArcList &arcList,
		NBestColl &nbestColl)
:indIter(0)
{
	// best
	NBest *contender = new NBest(mgr, arcList, 0, nbestColl);
	contenders.push(contender);
	bool extended = Extend(mgr, nbestColl, 0);
	assert(extended);
}

NBests::~NBests()
{
	BOOST_FOREACH(const NBest *nbest, m_coll) {
		delete nbest;
	}

	// delete bad contenders left in queue
	while (!contenders.empty()) {
		NBest *contender = contenders.top();
		contenders.pop();
		delete contender;
	}
}

bool NBests::Extend(const SCFG::Manager &mgr,
		NBestColl &nbestColl,
		size_t ind)
{
	if (ind < m_coll.size()) {
		// asking for 1 we've dont already
		return true;
	}

	assert(ind == m_coll.size());

	// checks
	if (ind >= mgr.system.options.nbest.nbest_size) {
		return false;
	}

	size_t maxIter = mgr.system.options.nbest.nbest_size * mgr.system.options.nbest.factor;

	// MAIN LOOP, create 1 new deriv.
	// The loop is for distinct nbest
	bool ok = false;
	while (!ok) {
		++indIter;
		if (indIter > maxIter) {
			return false;
		}

		if (contenders.empty()) {
			return false;
		}

		NBest *contender = contenders.top();
		contenders.pop();

		contender->CreateDeviants(mgr, nbestColl, contenders);

		if (mgr.system.options.nbest.only_distinct) {
			const string &tgtPhrase = contender->GetString();
			//cerr << "tgtPhrase=" << tgtPhrase << endl;
			boost::hash<std::string> string_hash;
			size_t hash = string_hash(tgtPhrase);

			if (distinctHypos.insert(hash).second) {
				ok = true;
			}
		}
		else {
			ok = true;
		}

		if (ok) {
			Add(contender);
			//cerr << best->GetScores().GetTotalScore() << " ";
			//cerr << best->Debug(mgr.system) << endl;
			return true;
		}
		else {
			delete contender;
		}
	}

	return false;
}

}
}

